Everyone has those cold and dark mornings, where it feels like even an IV of expresso couldn’t get you out of bed. But what if that mood doesn’t lift? An estimated 10 million Americans suffer from seasonal affective disorder (SAD), a mild depression that develops gradually as reduced exposure to sunlight disrupts the body’s internal clock, throwing off the production of sleep-regulating melatonin and mood-boosting serotonin. For those whose energy wanes as the leaves start to fall, this week I will be giving suggestions to help prepare yourself for the time change and winter months ahead.STRAIGHTEN UP: Look at how you are carrying your body. Are you vegging out on the couch watching TV? Slumping in front of your laptop? “Emotional states can be triggered by external cues,” says Erik Peper, PhD, a holistic healing professor at San Francisco State University. “If you look down or sit in a collapsed position, it will cue your brain to focus on the negative.”MOVE YOUR BODY: In a study from Duke University Medical Center, depressed people who worked out for 30 minutes at 75% of their maximum heart rate several times a week for 16 weeks felt just as much relief as those who took an antidepressant. Try a daytime outdoor jog, where you grab a little extra light. Yoga more your style? Choose a routine that focuses on holding chest-opening poses like back bends; a study from UCLA suggests they boost confidence and reduce negative thinking.GRAB HEALTHY COMFORT FOODS: If you’re craving sweets, skip apple pie and reach for a bowl of nuts and dark-chocolate chips instead. Magnesium-rich foods such as these may fight depression by supporting the function of serotonin and other mood-regulating hormones in the brain, according to a review published in the journal Medical Hypothesis.